The objective of this research is to study the epidemiology of congenital megacolon, to identify the etiologic factors related to the pathogenesis of this condition and to develop a prototype research design for epidemiologic investigations of other congenital malformations of the digestive tract. The first phase of this study will describe the epidemiology of all congenital malformations of the digestive tract requiring hospitalization in a defined population - children residing in metropolitan Baltimore. In the second phase of the study, an in-depth investigation into the epidemiology of congenital megacolon will be carried out through a case-control study. The characteristics of congenital megacolon patients and their families will be compared with those of control patients and their families to investigate the possibility that environmental factors, and specifically an infectious process may account for at least some cases of this condition in the United States. Thus, the objectives of this study will to: a. determine the incidence and prevalence of congenital malformations of the digestive tract; b. study changing trends in incidence of these conditions; c. identify the methodologic problems involved in ascertaining cases of these conditions; d. investigate the possible role of specific environmental factors including infectious agents in the etiology of congenital megacolon.